Outcome and Cost-effectiveness of Robot-assisted vs Laparoscopic Lateral Transabdominal Adrenalectomy

During the last twenty years, minimally-invasive surgery became the first choice for the surgical treatment of most of adrenal diseases. The advantages of minimally-invasive techniques are mostly to relate to the significative post-operative morbidity reduction. Adrenalectomy is a technical demanding procedure, requiring a cautious and precise dissection in the retroperitoneal space, so that endoscopic magnification may represent an essential tool. Several minimally-invasive approaches to adrenalectomy have been described, including anterior and lateral laparoscopic or lateral and posterior retroperitoneal techniques. Lateral transabdominal approach is the most frequently used for robotic adrenalectomy. However, routinary use of robotic platforms is limitated by their high costs.

Laparoscopic adrenalectomy was described by Gagner at al. in 1992, by means of a lateral transperitoneal approach. Several retrospective studies showed the advantages of laparoscopic approach compared to laparotomic procedure, such as lower post-operative pain, morbidity and hospital stay. Lateral transabdominal laparoscopic adrenalectomy is nowadays the most frequently used technique. One of the main advantages is related to the possibility of using the gravity effect during surgical dissection. Indeed, after the mobilization of the anatomic structures next to the adrenal gland (liver on the right side and splenopancreatic block on the left side), no more manipulations are necessary during the procedure. Moreover, this approach guarantees a wide working space, with the exposure of conventional anatomic landmarks, allowing an adequate vascular control. A further advantage consists in the possibility of exploring the whole abdominal cavity, therefore permitting the treatment of other surgical clinical conditions. Technically speaking, the main condition for the procedure success is a complete knowledge of surgical anatomy and an adequate surgical expertise, so that different approaches may be chosen basing on both patients' and lesions' features.

In 1999 Piazza et al. and Hubens et al. described robotic approach to adrenalectomy by means of AESOP 2000 platform. Then, "Da Vinci" platform (Intuitive Surgical, Sunnyvale, CA, USA) was introduced in clinical practice. After that, robotic adrenalectomies have been performed in several centers, proving the safety and feasibility of such procedure. "Da Vinci" platform allowed to maintain the same advantages of minimally-invasive approaches, with a reduction of the difficulties due to their technical limitations. Indeed, ergonomic superiority, tridimensional vision, tremors reduction and major freedom degrees related to the robotic instruments allow an easier surgical dissection.

Minimally-invasive adrenalectomy is the gold standard for the treatment of <6 cm adrenal lesions. Feasibility of endoscopic adrenalectomy for the treatment of wider or suspected for malignancy adrenal lesions still remains debated. National Institute of Health (NIH) Position Statement showed that adrenal cortical carcinoma prevalence is directly related to the lesion diameter, representing 2% of <4 cm lesions, 6% of 4,1-6 cm lesions and 25% of >6 cm lesions. However, lesion diameter alone is a too aspecific factor to be considered the parameter of choice of the surgical approach. Indeed, about 75% of >6 cm adrenal lesions result benign after definitive histological examination. Furthermore, several works in literature showed that the oncologic radicality of minimally-invasive approaches to localized malignant lesions is not inferior comparing to conventional laparotomic procedures. However, European Society of Endocrine Surgeon (ESES) and European Network for the Study of Adrenal Tumors (ENSAT) for the treatment of adrenal lesions suggest that transperitoneal approach should be the procedure of choice to guarantee optimal intraoperative stadiation, complete oncologic resection, capsular effraction risk and verify loco-regional structures infiltration.

Most studies demonstrated that TLA is a safe and effective procedure with low morbidity and mortality rates. Post-operative complications rates are not easy to interpretate due to the lack of standardization among the studies, though their range could be assessed between 2.9 and 15.5%. Complications and conversions risk factors, such as surgeon's expertise and center's volume, patient's anatomical characteristics and lesion's features, have been evaluated in monocentric and multicentric studies. More precisely, volume center and surgical expertise impact on clinical outcome have been demonstrated in several studies. Park et al. published a retrospective analysis of 344 adrenalectomies and documented a major complications rate (18.3 vs 11.3%) and a longer hospital stay (5.5 vs 3.9 days) in those procedures performed in center with low volume. Also, Palazzo et al. showed a significative increase in hospital stay and readmission within 30 days in low volume centers. Bergamini et al. identified age, BMI, lesion diameter and catecholaminergic secretion as risk factors for complications, with low complications rates in referral centers.